From a recent edition of mental_floss magazine:

In these tough economic times, any industry with significant job growth should be cheered, so here’s to Elvis impersonation. When Elvis died in 1977, there were 43 professional Elvii (that’s the plural form, because we said so). In 1990, there were 10,000. In 2000, some 35,000. At this rate, some have projected that one out of every three humans will be an Elvis impersonator by the year 2020.

“Fear Factors.” mental_floss Jul-Aug. 2004: 14